JPH04251816A - Raster scanner - Google Patents

Abstract

PURPOSE:To surely evade cases wherein an image becomes unbalanced in width at both ends in a main scanning direction when the length of an optical path is adjusted. CONSTITUTION:This raster scanner is characterized by the structure where at least one reflecting mirror 5 is supported by a movable support mechanism 7 movably at a constant angle attitude to an optical axis of incidence or an optical subframe 6a, equipped with a beam generating means 1, a beam deflecting means 3, and an image forming lens 4, which is supported by a movable support mechanism 8 movably at a constant angle attitude to an optical axis of projection.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raster scanning device that moves and scans a beam from a beam generating means along a main scanning direction of a photoreceptor, and particularly relates to a beam path between the beam generating means and a photoreceptor. This invention relates to an improvement in a raster scanning device that is provided with a mechanism for adjusting the length.

0002

2. Description of the Related Art Generally, examples of raster scanning devices include laser scanning devices used in laser printers and the like. As shown in FIG. 20, this includes a semiconductor laser 201 that emits a beam Bm according to an image signal, a polygon mirror 202 that distributes the beam Bm from the semiconductor laser 201 over a predetermined scanning range, and a polygon mirror 202 that distributes the beam Bm from the semiconductor laser 201 over a predetermined scanning range. beam Bm to the photosensitive drum 203
An imaging lens 2 that properly forms an image along the main scanning line of
04 and a reflecting mirror 205 that guides the beam Bm distributed by the polygon mirror 202 to the photosensitive drum 203 side. is precisely positioned on an optical frame (not shown) via the optical subframe 206 or directly.

However, since there are variations in the manufacturing precision and mounting precision of various parts, various adjustments are required to absorb variations in the precision of various parts, and one of these is optical path length adjustment. This is to adjust the distance from the polygon mirror 202 to the photosensitive drum 203 or the distance from the imaging lens 204 to the photosensitive drum 203 to match the exposure width (substantial scanning range in the main scanning direction) for a specified time. .

0004

By the way, as a conventional optical path length adjustment method, for example, in a type of supporting mechanism for the reflecting mirror 205, the reflecting mirror 205 is supported by three variably adjustable support points. For example, by variably adjusting the position of each support point, the position of the reflecting surface of the reflecting mirror 205 is moved in the optical axis direction, and the optical path length is variably adjusted. When the output image quality of a laser printer with adjusted optical path length was inspected, a technical problem was found in that the image width in the main scanning direction tends to be unbalanced at both ends of the image.

The inventor of the present application considered the cause of the above-mentioned technical problem, and when adjusting the optical path length by changing the positions of the reflecting mirror 205 and the imaging lens 204, for example, the method shown in FIG.
As shown by the dotted line in , it was concluded that this was caused by the movement direction of the reflecting mirror 205 being deviated from the optical axis direction, and when adjusting the optical path length, the image in the main scanning direction at both ends of the image was The present invention has been devised to reliably avoid the situation where the width becomes unbalanced.

[0006]

[Means for Solving the Problem] That is, the first invention, as shown in FIG. a beam deflection means 3 that deflects and scans the photoreceptor 2 in the main scanning direction; an imaging lens 4 that focuses the beam Bm deflected by the beam deflection means 3 on the main scanning line position S of the photoreceptor 2; , at least one reflective mirror 5 regulating the optical path between the beam deflecting means 3 and the photoreceptor 2.
and an optical frame 6 for positioning each of the components, at least one reflective mirror 5 is moved relative to the incident optical axis by a movable support mechanism 7 while maintaining a constant angular posture. It is characterized by being freely supported.

[0007] Furthermore, the second invention, as shown in FIG.
Beam generation means 1, beam deflection means 3, imaging lens 4,
Presuming a raster scanning device comprising at least one reflective mirror 5 and an optical frame 6, the beam generating means 1,
An optical subframe 6a equipped with a beam deflection means 3 and an imaging lens 4 is supported by a movable support mechanism 8 so as to be movable relative to the output optical axis while maintaining a constant angular posture. It is something.

Furthermore, a third invention is a raster system comprising a beam generating means 1, a beam deflecting means 3, an imaging lens 4, at least one reflective mirror 5 and an optical frame 6, as also shown in FIG. Assuming a scanning device, at least one reflective mirror 5 is supported by a movable support mechanism 7 so as to be movable with respect to the incident optical axis while maintaining a fixed angular posture, and also includes a beam generating means 1 and a beam deflecting means 3. The optical sub-frame 6a equipped with the imaging lens 4 is supported by a movable support mechanism 8 so as to be movable with respect to the output optical axis while maintaining a constant angular posture.

In such a technical means, the beam generating means 1 can be appropriately selected from a laser, a liquid crystal shutter, an LED, etc. as long as it can generate a beam Bm according to an image signal. In this case, the beam Bm may be irradiated corresponding to the image area, or
Alternatively, the beam Bm may be applied to a background area other than the image area.

The beam deflecting means 3 may be appropriately selected from a polygon mirror, a galvano mirror, etc. as long as it deflects the beam Bm from the beam generating means 1 along the main scanning direction of the photoreceptor 2. Also, regarding the imaging lens 4, the design of the lens configuration, number of lenses, etc. may be changed as appropriate as long as predetermined imaging characteristics can be obtained.

Furthermore, the configuration, number, layout, etc. of the reflecting mirror 5 may be modified as appropriate within the range in which a predetermined optical path length can be obtained. In this case, due to the tilting of the deflection surface of the beam deflection means 3, the beam Bm
Since there is a possibility that the scanning position of the beam Bm may shift, from the viewpoint of preventing this, it is necessary to install a tilt correcting means for the deflection surface of the beam deflecting means 3 (for example, a cylindrical mirror as one of the reflecting mirrors 5) in the path of the beam Bm. It is preferable to design the lens to include a cylindrical lens (cylindrical lens, etc.).

Furthermore, the structure of the optical frame 6 and the optical sub-frame 6a may be modified as appropriate as long as they have positioning parts for the various parts to be installed and the various parts can be fixed to each positioning part. It's okay to do that.

The design of the movable support mechanism 7 for the reflecting mirror 5 may be modified as long as it is capable of moving the reflecting mirror 5 along the direction of the incident optical axis; Considering that it is long in the direction perpendicular to the optical axis direction, the movable support mechanism 7 is as follows.
It is preferable to design the reflective mirror 5 so that the moving direction of the reflective mirror 5 can be reliably regulated, such as by providing a pair of positioning members extending in the direction of the incident optical axis on both sides of the reflective mirror 5. Furthermore, from the viewpoint of easily adjusting the amount of movement of the reflecting mirror 5, it is preferable to adopt a configuration in which the amount of movement of the reflecting mirror 5 is uniquely set depending on the position of the positioning pin, for example. .

The movable support mechanism 8 for the optical sub-frame 6a may be modified in design as long as it can move the optical sub-frame 6a along the output optical axis direction. In consideration of accurate movement, for example, it is preferable to design the optical subframe 6a so that the distance between two positioning pins that determine the direction of the optical subframe 6a is as long as possible.

[0015]

[Operation] According to the above-mentioned technical means, the movable support mechanism 7 moves the reflecting mirror 5 along the incident optical axis while maintaining the angular posture of the reflecting mirror 5. Without changing the beam Bm direction,
The optical path length from the beam deflection means 3 or the imaging lens 4 to the photoreceptor 2 changes. However, depending on the amount of movement of the reflecting mirror 5 along the incident optical axis and the set angle, it may be necessary to adjust the angle of the reflecting mirror 5 in order to maintain the incident position on the photoreceptor 2 at an appropriate position.

The movable support mechanism 8 also supports the optical subframe 6a while maintaining the angular posture of the optical subframe 6a.
Since the beam a is moved along the output optical axis, the direction of the output beam Bm from within the optical subframe 6a does not change, and the direction of the output beam Bm from within the optical subframe 6a remains unchanged.
The optical path length up to the point changes. Adjustments will be made.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments shown in the accompanying drawings. 2 and 3 show an embodiment of a laser scanning device to which the present invention is applied. In the same figure,
Reference numeral 20 denotes an optical subassembly attached to a predetermined portion of the optical frame 30, and this optical subassembly 20 includes a semiconductor laser 21 that irradiates a beam Bm according to an image signal, and a beam Bm from this semiconductor laser 21 that is parallel to each other. A collimator lens 22 that shapes the light, a polygon mirror 23 that deflects the beam Bm from the collimator lens 22 over a predetermined scanning range, and a reflecting mirror that reflects the beam Bm from the collimator lens 22 toward the polygon mirror 23. 24 and polygon mirror 23
An imaging lens 25 that properly forms an image of the beam Bm deflected by on the main scanning line S of the photosensitive drum 26 is disposed within the optical subframe 31 in a predetermined positional relationship.

Further, a synchronizing signal detector unit 27 is disposed near the optical subassembly 20 for detecting the image writing start position in the substantial scanning range of the photosensitive drum 26. 27 is Figure 3
It is movable in the two directions indicated by the middle arrow, and the position of the photosensitive drum 26 can be adjusted in the main scanning direction and the sub-scanning direction within one plane. More specifically, the synchronization signal detector unit 2
7, as shown in FIG. 4, a light receiving sensor 36 is disposed above the unit frame 35, and a reflection mirror 37 is disposed below the unit frame 35, so that the beam from the optical subassembly 20 is Bm is guided to the light receiving sensor 36 via the reflecting mirror 37, and if the position of the unit frame 35 with respect to the optical frame 30 is moved from the solid line to the dotted line in the direction corresponding to the sub-scanning direction of the photosensitive drum 26, , the position of the beam Bm to the light receiving sensor 36 in the sub-scanning direction can be adjusted. still,
By appropriately moving the position of the unit frame 35 with respect to the optical frame 30 in the main scanning direction perpendicular to the sub-scanning direction, the position of the beam Bm to the light receiving sensor 36 in the main scanning direction can be adjusted.

Furthermore, in this embodiment, a cylindrical mirror subassembly 28 for correcting the inclination of the mirror surface of the polygon mirror 23 is disposed on the optical frame 30. The beam Bm from the assembly 28 is irradiated to the outside of the optical frame 30 through an opening (not shown) formed in the optical frame 30, and is transmitted to the photosensitive drum through a reflection mirror 29 disposed on the back side of the optical frame 30. 26 main scanning lines S.

In this embodiment, the specific structure of the cylindrical mirror subassembly (hereinafter referred to as mirror subassembly in the embodiment section) 28 is shown in FIGS.
Mainly shown in FIG. In the figure, the mirror subassembly 28 includes a cylindrical mirror 41, a movable base 42 that is movable in the direction of the beam incident on the cylindrical mirror 41, and a movable base 42 that is provided on the movable base 42 so that the angle of the cylindrical mirror 41 can be adjusted freely. It is composed of a mirror support 50 that supports the mirror.

More specifically, the movable base 4
2 has positioning plates 44, 44 fixed to both sides of a highly rigid channel member 43 having a substantially hat-shaped cross section, and each positioning plate 44 has a cylindrical mirror 41 whose incident beam direction is fixed as shown in FIG. A plurality of (five in this embodiment) positioning holes 45a to 45 are formed along the
e are provided at intervals of, for example, L-X (mm), and on the other hand, a plurality (5 in this embodiment) of the optical frame 30 corresponding to each positioning plate 44 are provided along the direction of the incident beam of the cylindrical mirror 41. The frame side positioning holes 46a to 46e are opened at intervals of, for example, L (mm).

Then, by inserting the positioning pins 47 into the predetermined positioning holes 45a to 45e of the positioning plate 44 and the predetermined frame side positioning holes 46a to 46e, the position of the movable base 42 is adjusted as shown in FIG. It moves stepwise along the direction of the incident beam on the cylindrical mirror 41. In this embodiment, when the positioning pin 47 is inserted into the positioning hole 45c and the frame side positioning hole 46c, the state shown in FIG.
6a and 46e, the movable base 42 moves back and forth by 2X as shown in FIGS. 8(a) and 8(e) compared to the state in FIG. , 45d and frame side positioning holes 46b, 46d
When the positioning pin 47 is inserted into the position, the movable base 42 moves back and forth by X as shown in FIGS. 8(b) and 8(d) compared to the state shown in FIG. 8(c). At this time, both sides of the movable base 42 move by the same amount, so the movable base 42
2 does not deviate from the direction of the incident beam of the cylindrical lens 41. It goes without saying that the inserting position of the positioning pin 47 must be selected symmetrically between the left and right positioning plates 44.

Further, as shown in FIGS. 5 and 9, the mirror support 50 includes a pair of fixed plates 51 and 52 fixed to both sides of the movable base 42 in the longitudinal direction, and Rotation support plates 61 and 62 are rotatably mounted on the inner sides facing each other and support the cylindrical mirror 41.

More specifically, a mirror insertion opening 53 into which both ends of the cylindrical mirror 41 are inserted is provided in the center of the fixed plates 51 and 52, and
A rotation boss 54 as a rotation support shaft is formed in the vicinity of each mirror insertion opening 53.
is designed to provide a rotation center parallel to the generatrix of the cylindrical mirror 41. Furthermore, each fixed plate 51,
There are fixing screws 5 on both sides of the mirror insertion slot 53 of 52.
A pair of screw insertion holes 57 each having a larger diameter than those 5 and 56 are provided.

On the other hand, each of the rotation support plates 61 and 62
A mirror insertion opening 63 into which both ends of the cylindrical mirror 41 are inserted is provided at the center of the cylindrical mirror 41, and an engagement hole 64 into which the rotation boss 54 is rotatably engaged is provided at a location corresponding to the rotation boss 54. has been established. Furthermore, a pair of screw holes 67 into which the fixing screws 55 and 56 are screwed are formed on both sides of the mirror insertion opening 63 of each rotation support plate 61 and 62, respectively. Furthermore, an adjustment screw 68 that can freely protrude and retract downward is provided at the lower end of the rotation support plates 61 and 62 on the side away from the center of rotation, and the tip side of this adjustment screw 68 is attached to the surface of the movable base 42. They are placed in contact with each other. Therefore, by appropriately moving the adjustment screw 68 in and out, the rotation support plates 61 and 62 are slightly rotated around the center of rotation according to the amount by which the adjustment screw 68 is pushed.

[0026]The one rotational support plate 61
Of the mirror insertion slot 63 edge, the cylindrical mirror 4
At the location corresponding to the reflective surface 41a of 1, there is a reflective surface 41 of 2.
Support protrusions 71 and 72 are formed to support at points, and
A support protrusion 73 that supports the lower side surface 41b at one point is formed at a location corresponding to the lower side surface 41b orthogonal to the reflective surface 41a of the cylindrical mirror 41. Further, a support protrusion 74 that supports the reflective surface 41 at one point is formed at a location corresponding to the reflective surface 41a of the cylindrical mirror 41 on the edge of the mirror insertion opening 63 of the other rotational support plate 62, and a support protrusion 74 that supports the reflective surface 41 at one point Reflective surface 41 of mirror 41
A support protrusion 75 that supports the lower side surface 41b at one point is formed at a location corresponding to the lower side surface 41b orthogonal to a. Furthermore, in FIGS. 6(a) and 9(b), FIG. 9(a) (corresponding to the view seen from the direction A in FIG. 5) and (b) (corresponding to the view seen from the direction B in FIG. 5). As shown, each rotation support plate 61
, 62 are fitted with leaf springs 76 to 79, respectively, for biasing the cylindrical mirror 41 toward the respective support protrusions 71 to 75.

Next, a method of adjusting the angle of the cylindrical mirror 41 using the mirror support 50 will be explained. Now, assuming that the angle of the cylindrical mirror 41 is changed by θ, as shown in FIGS. 9(a) and 9(b),
First, by loosening each fixing screw 55, 56,
The rotation support plates 61 and 62 are kept in a rotatable state.

In this state, as shown in FIG. 9(a), by appropriately turning the adjustment screw 68 on the rotary support plate 61 side, the rotary support plate 61 side is rotated by θ, as shown in FIG. 10(a). As shown in , one end side of the cylindrical mirror 41 follows the rotational support plate 61 and rotates from the state shown by the dotted line to the state shown by the solid line. At this time, as shown in FIG. 10(b), since the rotation support plate 62 is also in a freely rotatable state, the other end side of the cylindrical mirror 41 also follows the rotational movement of the one end side of the cylindrical mirror 41. It rotates by θ together with the rotation support plate 62.

At this stage, if the fixing screws 55 and 56 are tightened, the cylindrical mirror 4
1 will be set at a position rotated by θ as a whole.

Cylindrical mirror 4 according to this embodiment
In evaluating the angle adjustment performance of No. 1, Fig. 13(a)(b)
As shown in FIG. 2, one configuration (rotation support plate 61 side) of the mirror support 50 is the same as that of the embodiment, and the other configuration (rotation support plate 62 side) eliminates the rotation support plate 62 and replaces the fixed plate with Support protrusions 74, 75 and plate springs 78 are provided in the mirror insertion slot 53 of 52, respectively.
, 79 was used as a comparative example, and the same mirror angle adjustment as in the example was performed for this comparative example.

In the above-mentioned comparative example, FIG. 14(a)
As shown in FIG. 14(b), when one end of the cylindrical mirror 41 was rotated and moved from the dotted line to the state shown by the solid line by appropriately rotating one rotational support plate 61, the cylindrical mirror 41 was initially The other end side follows the rotational movement of the one end side and rotates from the state shown by the dotted line to the state shown by the solid line. At this time, assuming that the lower side surface 41b on the other end side of the cylindrical mirror 41 is lifted off the support protrusion 75 by an amount Δ, the biasing force of the plate spring 79 will cause the cylindrical mirror 41 to rise as shown in FIG. 14(c). The other end of the cylindrical mirror 41 moves downward until the lower side surface 41b of the other end of the cylindrical mirror 41 comes into contact with the support protrusion 75, and the generatrix of the other end of the cylindrical mirror 41 moves downward. It deviates downward by Δ. This means that the generatrix of the cylindrical mirror 41 is tilted, which confirms that the angle adjustment performance of the mirror according to the comparative example is unfavorable, and that the mirror according to the example is superior.

Furthermore, in this embodiment, even if the generatrix of the cylindrical mirror 41 itself is tilted, it is possible to correct the inclination of the generatrix due to the manufacturing precision of the cylindrical mirror 41. The specific correction procedure will be described.

Now, assuming that it is found that the generatrix of the cylindrical mirror 41 is tilted at the time when the angle of the mirror is adjusted as described above, as shown in FIG. 11(b), one of the fixing screws is After loosening only the adjusting screw 56 and making the rotary support plate 62 rotatable, loosen the adjusting screw 68.
is adjusted appropriately to rotate the rotary support plate 62 by the amount of inclination correction, thereby correcting the inclination of the generatrix of the cylindrical mirror 41.

At this time, as shown in FIG. 11(a), one side of the mirror support 50 (rotation support plate 61
side), the rotary support plate 61 is fixed to the fixed plate 51 by the fixing screw 55, and the cylindrical mirror 41 is in a state in which the reflective surface of the cylindrical mirror 41 is in contact with the two support protrusions 71 and 72. 41 is restricted from moving in the rotational direction. Therefore, even if slight rotational movement such as correction of the inclination of the generatrix is performed on the other side of the mirror support 50, one end of the cylindrical mirror 41 will not follow the movement of the other end, and the cylindrical mirror 41 will not move following the movement of the other end. The slope of the generatrix is reliably corrected.

Incidentally, in a strict sense, FIGS. 12(a) and (b)
), a rotary support plate 61 with a two-point support configuration
Although the angle of the reflective surface 41a of the cylindrical mirror 41 changes on the side, the radius of curvature of the cylindrical mirror 41 normally used in laser printers etc. is sufficiently large, and the span between the rotation support plates 61 and 62 is smaller than the two-point support span. is sufficiently long, and the amount of correction of the inclination of the generatrix is very small, so the error δ of the reflecting surface 41a is extremely small and causes no problem in actual adjustment.

Therefore, in this embodiment, FIG.
As shown in a) and (b), by changing the position of the movable base 42 in the above-described procedure, the position of the cylindrical mirror 41 along the incident beam direction can be changed, thereby changing the output beam direction. The optical path length from the polygon mirror 23 or the imaging lens 25 to the photosensitive drum 26 is variably adjusted without changing.

Furthermore, as shown in FIGS. 15(a) and 15(b),
By adjusting the mirror support 50 according to the above-described procedure, the angle of the cylindrical mirror 41 can be adjusted and the generatrix can be corrected, so that the latent image is properly written on the main scanning line S on the photosensitive drum 26. .

Furthermore, in this embodiment, the optical subassembly 20 is adapted to be moved and adjusted along the direction of the output beam. To be more specific, FIGS. 16 to 18
As shown in FIG. 2, a position regulating pin 101 with respect to the output beam direction is provided on one side of the back surface of the optical sub-frame 31 of the optical sub-assembly 20, and this position regulating pin 10
1 is slidably engaged with a long hole 102 extending in the direction of the output beam in the optical frame 30. Further, on the other side of the back surface of the optical sub-frame 31, two position regulating pins 103 arranged in the direction of the output beam are protruded, and a screw for inserting a temporary set screw 104 in line with the position regulating pins 103 is provided. An insertion hole 105 is opened.

Further, a position adjustment plate 106 is interposed between the optical sub-frame 31 and the optical frame 30, and this position adjustment plate 106 is connected to the horizontal portion 1.
07 is formed in a long L-shape, and a long hole 108 extending in the direction of the output beam that engages with the position regulating pin 103 is formed in the horizontal portion 107, and also corresponds to the screw insertion hole 105. A screw hole 109 is formed into which a temporary set screw 104 is screwed, and a positioning pin 110 is protruded from the back side of the horizontal portion 107, and a positioning hole 111 that engages with the positioning pin 110 is formed in the optical frame 30. It has been established. On the other hand, a screw hole 113 for screwing an adjustment screw 114 is formed in the vertical portion 112 of the position adjustment plate 106. In addition, optical subframe 3
1 is formed with a stopper wall 115 that faces the vertical portion 112 and against which the tip of the adjustment screw 114 abuts.

Next, the installation state of the optical sub-frame 31 will be explained. The position adjustment plate 106 is temporarily assembled to the optical sub-frame 31 using the temporary set screws 104, and in this state, the length of the optical frame 30 is adjusted. The position regulating pin 101 of the optical sub-frame 31 is engaged with the hole 102, and the positioning pin 110 of the position adjustment plate 106 is engaged with the positioning hole 111 of the optical frame 30.

At this stage, if the adjusting screw 114 is rotated appropriately, the adjusting screw 114 will be moved to the stopper wall 115.
When the adjusting screws 114 are pushed in sequentially, the optical sub-frame 31 moves with its position regulated relative to the beam irradiation direction, and when the optical sub-frame 31 reaches a predetermined position. And the above temporary set screw 10
4, securely tighten the optical subframe 3.
1 is positioned at a predetermined position. Then, the optical subframe 31 is attached to the optical frame 30 using fixing screws (not shown).
Once the optical subframe 31 is fixed, the installation of the optical subframe 31 is completed.

Therefore, in this embodiment, FIG.
As shown in a) and (b), by appropriately rotating the adjusting screw 114, the optical sub-frame 31 can be moved along the beam emission direction m, and thereby the polygon mirror 23 or the It becomes possible to variably set the optical path length from the image lens 25 to the photosensitive drum 26.

[0043]

According to the invention as set forth in claims 1 to 3, the reflecting mirror or the optical subframe can be moved along the beam incident direction or the beam exiting direction while keeping the angular posture of the reflecting mirror or the optical subframe constant. Since it is moved, the optical path length from the beam deflection means or the imaging lens to the photoreceptor can be variably set while adjusting the optical path length while reliably avoiding deviation of the beam path.

Further, according to the second aspect of the invention, even if the optical sub-frame is moved along the beam emission direction, the position of the beam incident on the photoreceptor does not change, so that the optical sub-frame can be moved. The optical path length can be easily adjusted without requiring any angle adjustment.

Furthermore, according to the third aspect of the invention, the reflecting mirror and the optical subframe are moved along the beam incident direction or the beam exiting direction, respectively, while keeping the angular postures of the reflecting mirror and the optical subframe constant. Therefore, if the optical path length is adjusted for each subassembly for the reflective mirror subassembly and optical subassembly during assembly, even if each subassembly is replaced independently, the optical path length will be adjusted when replacing the parts. Length adjustment can be omitted.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an overview of a raster scanning device according to the present invention.

FIG. 2 is an explanatory front view showing an embodiment of a laser scanning device to which the present invention is applied.

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is an explanatory diagram showing a configuration example of a synchronization signal detector unit.

FIG. 5 is an exploded perspective view of the cylindrical mirror subassembly.

FIG. 6 is a front view (a) and a plan view (b) of a cylindrical mirror subassembly.

FIG. 7 is an explanatory diagram showing a positioning structure of a movable base.

FIG. 8 is an explanatory diagram showing the positioning state of the movable base.

FIG. 9 is an explanatory diagram showing a mirror support.

FIG. 10 is an explanatory diagram showing the angle adjustment state of the cylindrical mirror by the mirror support.

FIG. 11 is an explanatory diagram showing a state in which the inclination of the generating line of the cylindrical mirror is corrected by the mirror support.

FIG. 12 is an explanatory diagram showing how the mirror surface changes when the inclination of the generatrix of the cylindrical mirror is corrected by the mirror support.

FIG. 13 is an explanatory diagram showing an example of a mirror support according to a comparative example.

FIG. 14 is an explanatory diagram showing the angle adjustment state of the cylindrical mirror by the lar support according to the comparative example.

FIG. 15 is an explanatory diagram schematically showing the optical path length and angle adjustment state by the cylindrical mirror according to the example.

FIG. 16 is an explanatory diagram showing a position adjustment mechanism of the optical subframe.

FIG. 17 is an explanatory diagram of the main part thereof.

FIG. 18 is a view taken from below in FIG. 17;

FIG. 19 is an explanatory diagram schematically showing an optical path length adjustment state by the optical subframe according to the example.

FIG. 20 is an explanatory diagram showing an example of a conventional raster scanning device.

[Explanation of symbols]

1 Beam generation means 2 Photoreceptor 3 Beam deflection means 4 Imaging lens 5 Reflection mirror 6. Optical frame 6a Optical subframe 7 Movable support means 8 Movable support means

Claims (3)

[Claims] 1. Beam generating means (1) for generating a beam (Bm) according to an image signal;
A beam deflection means (3) deflects and scans the beam (Bm) from 1) over the main scanning direction of the photoreceptor (2), and a beam (Bm) deflected by the beam deflection means (3) is exposed to light. An imaging lens (4) for forming an image on the main scanning line position (S) of the body (2), a beam deflection means (3) and a photoreceptor (2).
) at least one reflective mirror (5) regulating the optical path between
) and an optical frame (6) for positioning each of the components, at least one reflective mirror (5) is moved by a movable support mechanism (7) to reflect the incident light while maintaining a constant angular attitude. A raster scanning device characterized in that it is supported movably about an axis. 2. Beam generating means (1) for generating a beam (Bm) according to an image signal;
A beam deflection means (3) deflects and scans the beam (Bm) from 1) over the main scanning direction of the photoreceptor (2), and a beam (Bm) deflected by the beam deflection means (3) is exposed to light. An imaging lens (4) for forming an image on the main scanning line position (S) of the body (2), a beam deflection means (4) and a photoreceptor (2).
) at least one reflective mirror (5) regulating the optical path between
) and an optical frame (6) for positioning each of the components, the beam generating means (1
), an optical subframe (6a) equipped with beam deflection means (3) and an imaging lens (4) is a movable support mechanism (8)
A raster scanning device characterized in that it is supported movably with respect to an output optical axis while maintaining a constant angular posture. 3. Beam generating means (1) for generating a beam (Bm) according to an image signal;
A beam deflection means (3) deflects and scans the beam (Bm) from 1) over the main scanning direction of the photoreceptor (2), and a beam (Bm) deflected by the beam deflection means (3) is exposed to light. An imaging lens (4) for forming an image on the main scanning line position (S) of the body (2), a beam deflection means (3) and a photoreceptor (2).
) at least one reflective mirror (5) regulating the optical path between
) and an optical frame (6) for positioning each of the components, at least one reflective mirror (5) is moved by a movable support mechanism (7) to reflect the incident light while maintaining a constant angular attitude. The beam generating means (1) and the beam deflecting means (3) are supported movably with respect to the axis.
and an optical subframe (
6a) is a raster scanning device characterized in that it is supported by a movable support mechanism (8) so as to be movable with respect to the output optical axis while maintaining a constant angular posture.